Educational Quality and Incident All‐Cause Dementia: Black‐White Differences

Abstract

AbstractBackgroundMeasurement of education via years of schooling may not be commensurate across racial and ethnic groups because of disparities in educational quality. We examine state‐level administrative school quality data and incident all‐cause dementia among Kaiser Permanente Northern California members who participated in a midlife survey and were aged 65 years or older at the start of follow‐up (1997).MethodsWe obtained educational attainment and birth state from surveys administered during 1964‐1973. We linked birth state with state‐level school quality measures (student‐teacher ratio, attendance rates, term length), categorized into tertiles using the overall sample. We obtained sex, race, and incident dementia diagnoses during follow‐up (1997‐2018) from electronic health records. Using race‐stratified Cox proportional hazards models (age as timescale), we estimated associations between each educational quality measure and dementia risk, adjusting for sex, birth region and educational attainment.ResultAmong 39,632 participants, 17% identified as Black, 44% reported less than high school education, and 7,206 individuals were diagnosed with dementia (mean follow‐up 13.5 years) (Table 1). Average educational quality was lower among Black participants (Table 1). Higher attendance rates and longer term length were associated with lower dementia risk among both racial groups (Figure 1, Table 2). Among Black participants, for example, highest versus lowest attendance rate tertile was associated with 50% lower risk (adjusted hazard ratio [HR]: 0.50, 95% confidence interval [CI]: 0.38‐0.67). Lower student‐teacher ratio was associated with lower risk only among White participants. The association between higher educational quality and lower dementia risk was stronger among Black than White participants for attendance rates and term length (race‐school quality interaction term p‐value: 0.05 and 0.03, respectively), but not significantly different for student‐teacher ratio.ConclusionIn both Black and White participants, higher school quality is associated with lower risk of incident dementia, even after adjusting for educational attainment. The associations were stronger among Black participants for attendance rates and term length. Educational disparities may partially be explained by lower average educational quality among Black participants, limiting its protective effects.